The invention relates to a fire extinguishing device, with at least one supply line that is dry with the device in an idle state, through which at least one extinguishing nozzle closed or open in an idle state is connected with an extinguishing fluid supply unit, which fills the supply line with an extinguishing fluid if a fire breaks out. Devices of this kind are used, for example in frost-endangered and especially sensitive areas, as stationary systems in structures like buildings or ships, so as to be able to effectively fight a blaze if a fire breaks out. The device can be triggered by separate fire alarm boxes, which monitor the respective room or area independent of the extinguishing nozzles. As an alternative or supplement, however, the extinguishing device can be activated by an element located on the extinguishing nozzle itself.
For example, such an element can be a glass vat, which bursts during a rise in temperature caused by a blaze, thereby opening an extinguishing nozzle that had been closed up to that point. The pressure drop that sets in as the extinguishing nozzles open in the supply line held under a specific excess pressure is detected by a pressure monitor, which activates the extinguishing fluid supply unit if the pressure drops below a minimal level in the supply line.
In order to increase the reliability of actuation, a test pressure lying distinctly over the ambient pressure is maintained inside the supply line in the above systems. In this way, the pressure drop is greater when opening the extinguishing nozzle, so that the opening of the respective extinguishing nozzle that accompanies the conflagration is reliably detected.
One problem in dry extinguishing systems of the kind described above is that the volume of air present in the supply line must be forced out by the extinguishing fluid introduced into the supply line in the event of a blaze. To this end, the expelled air must escape through the extinguishing nozzles, which may delay the exit of extinguishing fluid. This is particularly problematical in extinguishing devices in which an extinguishing mist is generated by the extinguishing nozzles out of an extinguishing fluid conveyed under an elevated pressure for effective firefighting that causes little water damage. In these devices, the extinguishing nozzles have particularly small hole cross-sections, which act as a kind of restrictor, impeding the outflow of air contained in the supply line.
Other devices also have one or more extinguishing nozzles that are closed in an idle state, and are filled with extinguishing fluid as soon as a fire detector, e.g., a smoke detector, which is used in addition to a tripping element secured to the extinguishing nozzle itself, sends out a signal. Therefore, the system is filled with extinguishing fluid independently of the opening of the extinguishing nozzle. Extinguishing fluid can only exit the extinguishing nozzle after the latter has been opened by a tripping element secured to it. The supply line can only be filled to the extent that the air contained therein can be compressed if the extinguishing nozzles have not yet been opened. If one or more extinguishing nozzles open, the air must first escape before the supply line can be completely filled with water.
The object of the invention is to improve a device of the type mentioned above with simple means in such a way that the air contained in the supply line can rapidly escape while filling with a high operational safety.
This object is achieved according to the invention by connecting the supply line with a discharge channel, in which a bursting disk, which seals the discharge channel in an idle state, and a valve, which closes at a pressure higher than the bursting pressure of the bursting disk, are situated one after the other in the discharge direction. The valve situated behind the bursting disk in the air discharge direction can here be easily realized by means of a check valve.
According to the invention, a discharge channel sealed in a special way in an idle state is provided, which ensures the rapid outflow of air while filling without any problem. To this end, the discharge channel is sealed by a bursting disk in an idle state. This bursting disk bursts at a specific bursting pressure. The bursting pressure can be selected in such a way as to lie slightly above the resting pressure to give a sufficient level of safety. This ensures that the bursting disk bursts with a rise in pressure, which is caused by the extinguishing fluid being filled into the air contained in the dry supply line. After the bursting disk has burst, the air contained in the supply line can pass through the discharge channel unimpeded via the downstream valve, and escape into the open. The valve situated in back of the bursting disk in the direction of airflow is here designed in such a way as to only close when exposed to the pressure of the extinguishing fluid. In this way, the combined arrangement according to the invention of a bursting disk and a valve that closes at a specific pressure ensures that the extinguishing fluid exits the respective extinguishing nozzle without delay after activation of liquid fluid supply unit.
The unimpeded, complete escape of the air sealed in the supply line can be ensured in a particularly effective manner by situating the discharge channel at the end of an extinguishing section. As an alternative, the discharge channel can be situated in the respective extinguishing nozzle itself. The extinguishing nozzles provided with discharge channels have a compact, functionally reliable design, which is easy to manufacture and assemble.
The invention is particularly well suited in relation to fire extinguishing devices in which the extinguishing fluid supply unit supplies the extinguishing fluid to the supply line under a high pressure. Precisely in these kinds of extinguishing systems, it must be ensured that the extinguishing fluid gets rapidly to the extinguishing nozzles, unimpeded by the air sealed in the supply line. The invention has proven itself as fit for use in practice precisely in those extinguishing devices that are especially problematical in conjunction with the conventional mode of venting, in which the extinguishing nozzle generates an extinguishing mist. Since the air sealed in the supply line does not have to escape through the extinguishing nozzle, the rapid discharge of extinguishing mist in the event of a blaze is ensured by this invention precisely in such systems, despite the small cross section of the nozzle holes.